silver,
Here is a set of instructions for
adjusting valve lash on 261/235/261 truck engines.
All 216/235/261 Chevrolet
truck engines came with mechanical (solid) lifters (some of the later truck blocks were made to accept hydraulic lifters but they came with solid/mechanical lifters). As stated above, from 1954 onwards, the 235 Chevrolet
automobile engine had hydraulic lifters (1953 PowerGlide engines did, too).
261 engines from Canadian Pontiacs had hydraulic lifters. I am not certain if later 235 truck engines with automatic transmissions came with hydraulic lifters (they did not in 1954/55).
Check out the
Tech Tips section of this website (the link is also listed at the top of this page) for a lot of good information - look in the "Engine" section of Tech Tips for more instructions on setting valve lash.
Tim